1. Technical Field
The invention relates to wireless public access to electronic networks. More particularly, the invention relates to an architecture that permits the creation of virtual basic service sets from within a physical access point for an electronic network.
2. Description of the Prior Art
Public WiFi hotspots are deployed using traditional IEEE Std. 802.11-compliant access points with some exceptions. However, the IEEE Std. 802.11 architecture and security model are unsuitable for public use. Stations associated with an access point (AP) share an 802.11 Basic Service Set (BSS), or wireless LAN. Unless all members of a BSS are trustworthy, no station in the BSS is safe from attacks initiated by other members. Such attacks include stealing the basic service and any confidential information provided by subscribers to get the service, such as passwords and credit card information. Other attacks include disruptions in network integrity and quality of service. It is unrealistic to expect all members of a public BSS, i.e. one that is comprised of stations associated with a public AP, to be trustworthy. Therefore, stations are vulnerable in a public BSS.
Sharing a public BSS presents another threat. Members of the BSS can contaminate other member stations with worms or Trojan horses. The port-based DCOM RPC attack, MSBlaster, and Welchia worms are good examples. The threat is more acute with a public BSS which is an electronic cesspool. How can a station cope with the threats?
Stations in the BSS might fend for themselves with defenses such as personal firewalls. Alternatively, a public WiFi provider might deploy a security model that protects subscribers from one another. One approach is to prevent inter-station communication. This is an untenable solution though. Stations that trust each other should be allowed to communicate among themselves, even in a public setting. Stations, for instance, should be able to access a file server on the same local LAN in a meeting held at a convention center. This is the usual practice at standards meetings, for example. Yet if this type of sharing is permitted, then under IEEE Std. 802.11, it becomes easy for an intruder to render the entire BSS inoperable. This was demonstrated at the 2001 Usenix Security Conference and at the 2001 DEFCON conference in Las Vegas. No security model today for wireless LAN can support this type of sharing without introducing vulnerabilities.
It would be advantageous to provide a security model for wireless LAN that can support sharing of a single physical BSS without introducing vulnerabilities or compromising security among stations using the BSS.